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7.B.7 Transformer
This appliance’s transformer is not capable of
supplying control voltage for external devices such
as zone valves, which must have their own separate
power supply. Should a transformer need replacing,
shut off the 120-volt power. Unplug the transformer
wires, remove the mounting screws and remove the
transformer. Replace transformer in the reverse order.
7.B.8 Flow Switch
This appliance uses a paddle-type flow switch to
ensure that the unit has water flow before ignition is
allowed. To replace the flow switch, turn off the 120-
volt power to the appliance. Isolate the boiler or water
heater from the system by closing the isolation valves.
Caution
Water may be hot enough to scald. Allow water to
cool before proceeding.
Attention
L’eau peut être chaude au point de vous brûler.
Laissez refroidir l’eau avant d’intervenir.
Release pressure in the system by actuating
the pressure relief valves or field supplied boiler
drain valve. Remove cover from the flow switch
and disconnect the wires. Unthread the flow switch
from piping. Ensure the new flow switch paddles are
trimmed to the same size as the original paddles, and
reinstall in the reverse order. For boiler and other static
pressure systems, restore the system pressure to the
original setting, (or 10 psi minimum).
7.B.9 Heat Exchanger Coil
This appliance has a premixed burner system.
These systems provide the burners with sufficient air
for complete combustion, and black carbon sooting is
seldom experienced. If sooting is suspected, view ports
for inspection of the heat exchanger are provided on
the side of the boiler. In the unlikely event that there is
a buildup of black carbon soot or other debris on the
heat exchanger, clean per the following:
1. Disconnect the electrical supply to the unit.
2. Turn off the gas supply by closing the manual gas
valve on the heater.
3. Disconnect and remove the wires, conduit and
sensors from all components that are attached to
the inlet/outlet header.
4. Isolate the heat exchanger from the water supply.
5. Disconnect the header flanges from the inlet and
outlet.
6. Allow the heat exchanger to drain. Remove the
venting and remove the top, by removing the
screws that attach the top to the side panels.
Remove the side panels.
7. Remove the heat exchanger from the unit.
NOTE: Heat exchangers are heavy and may
require two people to remove to avoid personal
injury.
8. Clean the heat exchanger: A light accumulation
of soot or corrosion on the outside of the heat
exchanger can be easily removed. Use a wire
brush to remove loose soot and scale from the
heat exchanger.
9. NOTE: While the heat exchanger is out of the
unit, inspect the firewall refractory insulation.
Replace if necessary.
10. Inspect the inside of the copper tubes for scale
buildup. Scale can build up on the inner surface
of the heat exchanger tubes, which can restrict
water flow. If the tubes show signs of scaling,
clean the internal surface.
11. Reassemble in the reverse order, and check
appliance operation after start-up.
NOTE: The warranty does not cover damage
caused by lack of required maintenance, lack of
water flow, or improper operating practices.
WARNING
Black carbon soot buildup on a dirty heat
exchanger can be ignited by a random spark or
flame thereby creating a risk of fire or explosion.
To prevent this from happening, dampen the soot
deposits with a wet brush or fine water spray
before servicing the heat exchanger.
AVERTISSEMENT
L’accumulation de suie sur un échangeur
thermique sale peut s’enflammer au contact
d’une étincelle ou d’une flamme et présenter un
risque d’incendie ou d’explosion. Afin d’empêcher
que cela se produise, humidifier les dépôts
de suie à l’aide d’une brosse mouillée ou par
une pulvérisation fine d’eau avant d’effectuer
l’entretien de l’échangeur thermique.
Mighty Therm
2
(200, 300, 400) Install & Operating
